(1) Field of the Invention
The present invention is related to the field of recipient lists for encrypted documents, more specifically, the method and apparatus of the present invention is related to embedding permission attributes into a recipient list listing recipients of encrypted documents.
(2) Related Art
Secured access to data including documents may be provided through use of passwords. For example, the document format referred to as the Portable Document Format (PDF) provides a mechanism whereby secure access to the data in a PDF file can be controlled through the use of passwords. This mechanism provides for two general categories of document recipients. One is an owner and the other is a user. An owner typically has one password and the user has another password. Thus, there are only two passwords associated with an encrypted document. When issued, the owner's password enables a user to gain full access and control of a document. The user password, when issued, enables the user to gain limited access to the document as defined by the owner.
There are several disadvantages to existing methods of providing secure access to a document. For example, in order for a recipient to gain access to a document, the user (or owner) password must be made available and all recipients must use the same user (or owner) password. Additionally, currently available methods only provide two levels of access, namely an owner and a user level of access. However, different identified users may need to be privileged with different levels of access to a document.
It is therefore desirable to associate permissions to recipients of a document providing them variable levels of access to the document and use of a dedicated access key providing access to the document.